I rarely have any issues finding Python libraries that don't work on Windows. PHP Development has become much easier on Windows that it has been in the past. One of my personal glaring exceptions is having a working memcached extension for PHP on Windows.
How many people do you know that actually know how to administer a system? And I do mean administer, not throw on/off a few switches in a conf file and hope it all works. I've lost count of how many times I've seen questions on forums on how to get two or more pieces of technology to talk to each other well enough. Sometimes well enough, isn't well... enough. Especially when real money is involved.
"I work with x and I need it to work with y and give me z amount of throughput" can be very complicated. Especially when the wiring is only sort of familiar to the user from a previous encounter doing some home tinkering.
Many engineers who build native apps on Linux can claim 'i know linux'. Native is an important distinction, as many good java developers for example have no clue what is going on down the stack.
For the 'I know how to scale on linux stack', I'd think the fastest way would be for you to look into a (1) system imager (e.g. kickstart) and a (2) configuration management system (e.g. puppet or chef). This will bring you scale and management. Throw in a (3) monitoring/alerting system (e.g. nagios and cacti). Finally, put your coding skills to work by building a small app that glues all the above together.
In the RH world, you do have the certification path, and a supply of good SAs who have worked in professional, systems-focused capacities. Most of the old Unix guys who are still around doing SA work have certs on the RH stack.
On the Ubuntu side, many of the people I see who claim "Ubuntu" subject matter expertise are basically Mac users who have more comfort working in the shell. That's a testament to the improvements in the Linux ecosystem from a desktop POV, but not so good if you are trying to hire people! Obviously, the wizards are out there, but they are hard to find.
The best thing is, it gives you the incentive to get a more well rounded skillset and understanding.
I would do it, if you did it half assed there are some training books for LPIC-1 I would start with.
Stuff like that is easily tax deductible, or maybe your employer would pay for it and it's not that much.
PS: I wanted to do it, but then got more into programming. Still very helpful the stuff I learned back then.